In performing surgery, particularly on the ear, it has been conventional to utilize a surgical instrument having an elongated handpiece with a rotatable tool projecting outwardly from the forward end thereof. This instrument is less than satisfactory since the straight handpiece results in the surgeon's hand, where it grips the handpiece, obstructing the surgeon's view of the tool and of the surgical area.
To improve upon such surgical instrument, particularly for use in ear surgery, it has been proposed to utilize an instrument wherein the handpiece assembly is angled. While the handpiece member again includes an elongated gripping portion, it also includes a nose portion for rotatably supporting the tool, which nose portion extends at an angle of 20.degree. relative to the gripping portion. This instrument, however, has been discovered to possess features which make usage of same less than desirable when performing ear surgery. For example, the angular relationship between the nose and hand portions still results in the hand of the surgeon being at least partially disposed within the surgeon's line of sight. This angular relationship also does not provide the surgeon with the desired feel and control which is desired to permit proper manipulation of the instrument during the surgical procedure.
The known surgical instruments of this general type have also possessed other features which have made their use less than satisfactory. For example, these known instruments have normally employed a built-in motor and speed reducer mechanism whereby replacement of the motor and/or speed reducer so as to provide various speed ratios has thus been difficult and time-consuming, since such variations generally require a complete disassembly and rebuilding of the instrument. In addition, these known instruments have often been provided with a tool mounting structure which is less than satisfactory, particularly when the instrument is utilized with an elongated tool such as commonly employed in ear surgery.
The present invention thus relates to an improved surgical instrument which possesses features which makes same highly desirable for use in ear surgery, which instrument overcomes the above-mentioned shortcomings.
More specifically, it is an object of the present invention to provide an improved surgical instrument, as aforesaid, wherein the handpiece has an elongated grip portion and a shorter nose portion, which nose portion extends at an angle of 40.degree. with respect to the longitudinal axis of the grip portion so as to permit optimum gripping, handling and control of the instrument, while maximizing the surgeon's vision of the surgical area and tool.
It is also an object of this invention to provide an improved instrument, as aforesaid, which possesses both a cartridge-type motor and a cartridge-type speed reducer positioned within the handpiece, which cartridges can be easily and quickly removed and interchanged to permit replacement of same for purposes of repair or for producing a different speed ratio.
A further object of this invention is to provide an improved instrument, as aforesaid, which has a tool mounting structure associated with the nose portion of the handpiece for permitting an elongated rotatable tool, such as a burr, to be easily and readily attached to or removed from the instrument, while at the same time providing for proper support of the elongated tool so as to maintain same properly aligned during rotation of the tool.
In addition, this improved structure permits the utilization of an elongated burr having a tapered hub which coacts with a sleevelike mounting member to create a smooth exterior surface which minimizes contamination of the tool, which sleevelike member can be easily connected to or removed from the handpiece assembly.
To summarize the present invention, the surgical instrument is provided with an angled tubular handpiece which includes an elongated grip portion having a cartridge-type motor and a cartridge-type speed reducer removably positioned therein. The rearward end of the grip portion is connected to a suitable source for driving the motor, such as a flexible conduit for supplying pressurized air to the motor. The handpiece has a nose portion fixed to the other end of the grip portion, which nose portion extends at an angle of 40.degree. with respect to the longitudinal direction of the grip portion. This nose portion has a releasable torque-transmitting drive connection associated therewith. A tool assembly is adapted for connection to the nose portion of the handpiece assembly. The tool assembly includes an elongated burr or other suitable tool having an elongated shank rotatably supported within an elongated support sleeve, which support sleeve in turn has coupling structure adapted for releasable connection with further coupling structure mounted within the nose portion.
Other objects, purposes and advantages of the surgical instrument according to this invention will be apparent to persons familiar with instruments of this type upon reading the following specification and inspecting the accompanying drawings.